21416641 has 2 divisors, whose sum is σ = 21416642. Its totient is φ = 21416640.

The previous prime is 21416609. The next prime is 21416669. The reversal of 21416641 is 14661412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13660416 + 7756225 = 3696^2 + 2785^2 .

It is a cyclic number.

It is not a de Polignac number, because 21416641 - 2⁵ = 21416609 is a prime.

It is not a weakly prime, because it can be changed into another prime (21416671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10708320 + 10708321.

It is an arithmetic number, because the mean of its divisors is an integer number (10708321).

Almost surely, 2^21416641 is an apocalyptic number.

It is an amenable number.

21416641 is a deficient number, since it is larger than the sum of its proper divisors (1).

21416641 is an equidigital number, since it uses as much as digits as its factorization.

21416641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1152, while the sum is 25.

The square root of 21416641 is about 4627.8116858835. The cubic root of 21416641 is about 277.7050552680.

The spelling of 21416641 in words is "twenty-one million, four hundred sixteen thousand, six hundred forty-one".